CDC Reports Low Antibiotic Susceptibility in Fever Cases

Researchers urge doctors to reconsider standard antibiotic treatments for enteric fever due to high rates of drug resistance.

Updated on Oct. 28, 2026 in Diseases — General

Isometric editorial illustration of a glass petri dish containing a geometric bacterial growth pattern, representing antibiotic resistance research. — CDC researchers report that Salmonella Typhi and Paratyphi strains increasingly resist common antibiotics, requiring new approaches to treating enteric fever cases in the U.S. AI Illustration. Upload story photo >

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Should doctors prioritize updated antibiotic resistance data when determining standard treatment protocols?

CDC researchers studying 2,342 enteric fever cases across 47 U.S. states between 2016 and 2020 found widespread resistance to common antibiotics. The study, published in October 2026, reveals that the vast majority of Salmonella Typhi and Paratyphi isolates are no longer susceptible to ciprofloxacin.

Why it matters

The emergence of antibiotic-resistant strains, particularly those first identified in Pakistan in 2016, threatens the efficacy of treatments used since the 1980s. This shift forces a change in how clinicians approach empiric therapy for patients returning from international travel.

Researchers identified 2,342 enteric fever cases in the U.S. between 2016 and 2020, with 81.9% of patients reporting recent international travel. Analysis showed 78.4% of Salmonella Typhi and 94.2% of Paratyphi isolates lacked susceptibility to ciprofloxacin.

The players

CDC

The Centers for Disease Control and Prevention is the national public health agency of the United States.

The details

The study utilized samples from the National Antimicrobial Resistance Monitoring System to examine resistance trends. While most cases remain treatable with other classes of antibiotics, 5.5% of Typhi isolates showed resistance to ceftriaxone, a critical concern for medical providers.

1980s: Ciprofloxacin became the standard first-line treatment for enteric fever.
2016: Extensively drug-resistant Salmonella Typhi was first identified in Pakistan.
2016-2020: Period analyzed by researchers for domestic enteric fever cases.
October 2026: Findings were officially published in JAMA Network Open.

Health Landscape

This study relies on the National Antimicrobial Resistance Monitoring System to track evolving pathogen behavior in a globalized healthcare environment. These findings represent a significant update to previously held assumptions regarding the clinical effectiveness of standard fluoroquinolone treatments.

Patients who have recently traveled internationally and develop a fever should inform their doctor of their travel history to ensure appropriate diagnostic testing. Clinicians are now advised to avoid relying on ciprofloxacin as an initial treatment while awaiting lab results.

The takeaway

Clinicians and travelers should recognize that standard fever treatments may no longer be effective due to global increases in drug resistance. Prioritizing targeted antibiotic therapy based on lab susceptibility testing is becoming essential for recovery.